In Parker’s 35th Spenser novel, the likable and tough gumshoe trails the wife of a client who thinks she’s cheating on him.

This turns out to be true. And then the wife is killed, and the client (who turns out to be an FBI agent) is found dead. Spenser thinks he’s stumbled upon something that’s not only related to terrorism but also recalls some bad, unresolved moment in the past with his main squeeze, Susan Silverman.

Where the book falls flat is in Spenser’s motivation — something in his past with Susan prompts him to keep working on the deadly case (and unpaid at that, even though he needs hired guns to help protect him) and to give what he knows to the FBI.

Though Spenser’s helpers — Hawk and Vinnie — add both humor and deep knowledge of weaponry, they can’t help rescue the convoluted plot.